I saw there are ones that are round, square, and also have holes in them....any advantages or disadvantages to any of these?

I use a large round one with holes for removing excess bench flour from the bottom of the pie and loading into oven. I use a small round one for turning and removing the pie from the oven. I use a rectangular one for loading/unloading pizza bianca, rustic loaves, baguettes, calzones, etc., and removing ashes.

AH HaThanks Bill! To remove excesss flour (DUH) thats the reason for the holes. I know I still have a lot to learn. I thought it was for like anti friction or something.Last time I used metal (solid ) for getting into the wood fired oven I had a sticking issue. So I stick (no pun intented ) to wooded peel ( minimal flour now) to load, all else is done with the 8" metal circular peel. I remember when I got that with the oven I said "what the heck an I going to do with this little thing?" Now I say "what would I do with out it!" I did get a shovel from Fankie G to mess with the coals and that has been a improvement over messing up my key tool.John